IPC-T-50F_.pdf.pdf - 第75页
Twist 60.1553 The deformation of a rectangular sheet, panel or printed board, that occurs parallel to a diagonal across its surface, such that one of the corners of the sheet is not in the plane that contains the other t…
Torsional Strength 74.1095
The torque required to separate adhesive-bonded (and
cured) materials and/or components. (See also ‘‘Lap Shear
Strength’’ and ‘‘Shear Strength.’’)
Touch-Up 92.1097
The identification and elimination of defects in a product.
Trace 22.1098
see ‘‘Conductor.’’
Track 22.1099
see ‘‘Conductor.’’
Transfer Soldering 75.1101
The use of a soldering iron to transfer a measured amount
of solder, in the form of a ball, chip, or disc, to a solder
connection.
Transfer-Bump Tape Automated Bonding 74.1100
Tape automated bonding that uses discrete bumps between
the die lands and carrier tape to facilitate inner-lead bond-
ing.
Transmission Cable 21.1102
Two or more transmission lines in the form of an
interconnection-wiring cable.
Transmission Line 21.1103
A signal-carrying circuit with controlled conductor and
dielectric material physical relationship such that its elec-
trical characteristics are suitable for the transmission of
high-frequency or narrow pulse electrical signals. (See also
‘‘Balanced Transmission Line,’’ ‘‘Microstrip’’ ‘‘Stripline,’’
and ‘‘Unbalanced Transmission Line.’’)
Transmittance 24.1104
The ratio of the amount of light that is transmitted through
an object or material to the quantity of light that is incident
upon it.
Treatment Transfer 92.1548
The transfer of copper-foil treatment to a base material as
indicated by the presence of black, brown or red streaks
after the copper has been removed by etching.
Treeing 53.1549
A dendritic-type of plating growth that extends onto the
surface that is adjacent to edge of a conductive pattern.
(This is normally caused by excessive plating current.)
Tri-State 21.1105
A high-impedance state of an electronic device that effec-
tively disconnects the device output from all other cir-
cuitry.
Trim Lines (Pattern) 22.1106
Lines that define the borders of a pattern. (See also ‘‘Cor-
ner Marks.’’)
Trim Lines (Printed Board) 22.1550
Lines that delineate the border of a printed board. (See also
‘‘Corner Marks.’’)
Trimming 77.1108
The cutting of a film component by a laser beam or abra-
sive jet in order to modify its value.
Trimming Notch 77.1109
see ‘‘Kerf.’’
True Position 22.1110
The theoretically-exact location for a feature or hole that is
established by basic dimensions.
True Position Tolerance 22.1111
The total permissible deviation from a true position.
Trumeter 44.1112
A device used to accurately measure yardage passing a
specific point of reference.
Truth-Table Testing 21.1551
The application of electrical signals in accordance with a
prescribed logic matrix pattern that indicates the outputs
that should result from a given pattern of inputs.
Tuberculation 76.1113
The formation of localized corrosion products that are scat-
tered over a surface in the form of knob-like mounds.
Turnkey System 11.1114
A self-contained hardware and software system that per-
form a specific task.
Turret Solder Terminal 37.1552
A round post-type stud (stand-off) solder terminal with a
groove or grooves around which one or more wires are
wrapped prior to soldering. (See Figure T-1.)
IPC-I-001034
Figure T–1 Turret solder terminal
TOP SHOULDER
UPPER POST SELECTION
LOWER POST SELECTION
BASE
SINGLE TURRET DOUBLE TURRET
IPC-T-50F June 1996
70
Twist 60.1553
The deformation of a rectangular sheet, panel or printed
board, that occurs parallel to a diagonal across its surface,
such that one of the corners of the sheet is not in the plane
that contains the other three corners.
Two-Layer Carrier Tape 36.1554
The carrier for conductors used in tape-automated bonding
that consists of a dielectric layer with a layer of plated/
etched conductors. (See also ‘‘Multilayer Carrier Tape,’’
‘‘Single-Layer Carrier Tape,’’ and ‘‘Three-Layer Carrier
Tape.’’)
Two-Piece Contact 37.1115
A type of discrete connector contact that mates with
another discrete formed-metal connector contact. (See also
‘‘Edge-Board Contact.’’)
Two-Sided Board 60.1116
see ‘‘Double-Sided Board.’’
Type I Error 91.1117
The rejection of a hypothesis that is true.
Type II Error 94.1118
The accepting of a hypothesis that is false.
U
Ultrasonic Bonding 74.1119
A termination process that uses ultrasonic-frequency vibra-
tion energy and pressure to make the joint.
Ultrasonic Cleaning 76.1120
Immersion cleaning that is done by passing high-frequency
sound waves through a cleaning medium to cause micro-
agitation.
Ultrasonic Soldering 75.1121
Fluxless soldering wherein molten solder is vibrated at
ultrasonic frequencies while making the joint.
Unbalanced Transmission Line 21.1556
A transmission line that has distributed inductance, capaci-
tance, resistance, and conductance elements that are not
equally distributed between its conductors.
Uncased Device 35.1122
A component without a package.
Unconditional Test 92.1123
A test without limitations or restrictions on test mode, test
time, etc.
Undercut, After Fabrication 92.1124
The distance, measured parallel to the surface of a printed
board, from the outer edge of a conductor (excluding over-
plating and coatings) to the maximum point of the indenta-
tion on the same edge of
Undercut, In Process 92.1125
The distance, measured parallel to the surface of a printed
board, from the outer edge of a conductor (including etch
resist) to the maximum point of the indentation on the
same edge of the conductor. (See also ‘‘Undercut, After
Fabrication.’’)
Underwriters Symbol 94.1126
A logotype that denotes that a product has been recognized
(accepted) by Underwriters Laboratories, Inc. (UL).
Unfil 44.1127
A device attached to the loom which automatically winds
yarn onto quills from yarn packages and maintains a sup-
ply of quills for the shuttle.
Unload Time 92.1128
The time required to remove a unit from the evaluation
equipment, to collect the evaluation data, and to make the
system ready for the next unit.
Unsupported Hole 22.1129
A hole in a printed board that does not contain plating or
other type of conductive reinforcement.
Upload (Test) 92.1130
The ability of an analyzer to accept test program data from
a host computer.
Usable Resolution 52.1131
The smallest image and separation that can be produced,
and subsequently processed, in a given emulsion or thick-
ness of photoresist.
User Inspection Lot (Material) 91.1132
All of the material of the same type and, as far as practical,
of the same type designation that is produced from the
same equivalent batches or lots of constituent material
under essentially the same conditions and that is offered for
inspection at one time.
V
Vacuum Evaporation 53.1133
The deposition of a metal film onto a base material by
evaporation techniques.
Vacuum Head 73.1775
A handling instrument with a small vacuum cup which is
used to pick up clip devices and other surface mounting
devices.
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71
Vapor-Phase Soldering 75.1557
A reflow soldering method that is based on the exposure of
the parts to be soldered to hot vapors of a liquid that has a
boiling-point that is sufficiently high to melt the solder
being used.
Variables Data 91.1134
Quantitative data where measurements are used for analy-
sis.
Variance 91.1135
A measure of dispersion that is equal to the square of the
average value of deviation from a mean value.
Vendor Inspection Lot (Material) 91.1558
All of the material of the same type that have been fabri-
cated within a specified period of time using the same pro-
cessing procedures and conditions that are offered for
inspection at one time.
Verification Time 91.1136
The time required to determine an anomalies location, to
evaluate it, and to classify it with respect to predefined cri-
teria.
Very Large Scale Integration (VLSI) 30.1559
Integrated circuits with more than 80,000 transistors on a
single die that are interconnected with conductors that are
1 micron or less in width.
Vesical 92.1137
A blister formed as the result of vesication.
Vesication 92.1560
The formation of blisters at the interface between a semi-
permeable polymer film coating another material caused by
an osmotic effect from the interaction of water soluble mat-
ter with moisture. (See also ‘‘Measling.’’)
Vesicativity Ratio 92.1561
The ratio of the degrees of vesication produced by a spe-
cific mass of a substance to the degree of vesication pro-
duced by the same mass of sodium chloride under the same
specific conditions.
Via 22.1562
A plated-through hole that is used as an interlayer connec-
tion, but in which there is no intention to insert a compo-
nent lead or other reinforcing material. (See also ‘‘Blind
Via’’ and ‘‘Buried Via.’’)
Virtual Condition 91.1138
The boundary generated by the collective effects of
maximum/least material condition limits of size of a fea-
ture and any applicable geometric tolerances.
Visual Examination 92.1139
The qualitative observation of physical characteristics with
the unaided eye or within stipulated levels of magnifica-
tion.
Void 90.1140
The absence of any substances in a localized area.
Voltage Plane 22.1563
A conductor layer, or portion thereof, that serves as a com-
mon voltage source at other than ground potential for an
electrical circuit, shielding, or heat sinking. (See also
‘‘Ground Plane’’ and ‘‘Signal Plane.’’)
Voltage Plane Clearance 22.1141
Removed portions of a voltage plane that isolate it from a
hole in the base material to which the plane is attached.
Volume Ratio (Composite) 41.1142
The proportional thickness of one component of a compos-
ite material to the total thickness of the composite.
Volume Resistivity 21.1143
The ratio of the electrical potential gradient parallel to the
current in a material to the current density, expressed in
Megohm-meters.
Volumetric Analysis 92.1144
The measurement of the volume of solution consumed in a
titration process.
W
Wafer 35.1145
A thin slice of semiconductor crystal ingot that is used as a
base material.
Waffle Pack 71.1146
An open compartmentalized container for holding surface-
mount components that is suitable for loading the compo-
nents into automatic handling equipment.
Warp 60.1147
see ‘‘Bow.’’
Warp Size 44.1149
Organic yarn binder (starch) applied to the warp yarn to
improve strand integrity, strength and smoothness in order
to withstand the rigors of weaving. (See also ‘‘Sizing’’ and
‘‘Heat Cleaning.’’)
Warper 44.1148
A machine for preparing and arranging the yarns intended
for the warp of the fabric.
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